“Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035.”

The quotation is from the Fourth Assessment Report issued by the Intergovernmental Panel on Climate Change (“IPCC”) in 2007. It’s a sobering statement about the impact and pace of global climate change — an astonishing vanishing of the glaciers of the Himalaya in only 25 years.

It is also wrong.

The categorical nature of the statement has caused much criticism and embarrassment for the IPCC, which has significant impact on the formation of laws to implement climate policies by nations around the world. It does, however, provide a fitting example of the role of scientific peer review and the sweeping impact that errors in that process can potentially have.

The IPCC was formed in 1988 by the World Meteorological Organization and the United Nations Environment Programme. Its principal role is to assess the scientific information available about climate change and to issue assessment reports that are used by governments in developing laws and policy. Together with former Vice President Al Gore, it was awarded the Nobel Peace Prize in 2007 for “efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change.” There is no doubt that when its credibility is tainted by bold statements that turn out to be false that it fails, at least in part, in achieving that goal.

The incorrect statement apparently has its origins in a statement made by Syed Iqbal Hasnain, an Indian scientist, in 1999. He claims he was misquoted in an interview with the science magazine New Scientist: “I had simply told the New Scientist in an interview that the mass of the glaciers will decline in 40 years…. The date (2035) was their invention.” He acknowledges that his statement itself was based on data published in the 1970’s.

When the IPCC was preparing its Assessment Report, it was subject to peer review, which is the process scientists use to evaluate statements before publication. Peer review is always important, but it is especially so when pronouncements are being made by a body with the influence that the IPCC has. That process failed in this case. But what is notable is that the statement about the Himalaya was noted and questioned by at least some of the peer reviewers — one of whom pointed out a glaring inconsistency: “100,000? You just said it will disappear.”

Another of the peer reviewers noted that the statement seemed to be at odds with other research suggesting that glaciers in the Himalaya are actually expanding, pointing out specific references that should be consulted in assessing its validity.

The end result is that the report failed to account for the criticisms of the peer reviewers and instead retained a statement that was not itself validated by peer review. In the time since the error has been pointed out, there have been numerous allegations whose veracity is hard to assess: that the statement was included deliberately, even knowing it was wrong, to prompt action by governments; that Hasnain is being untruthful when he claims not to have mentioned a date; that those involved with publication of the statement have financial interests that would be enhanced by concerns the Himalayan glaciers are rapidly disappearing; and others. Any of these would be cause for additional concern if substantiated, but my focus today is more narrow: The peer-review system worked up to a point, with peer reviewers identifying the weaknesses in the statements. But it takes attention and diligence on the part of all involved with that process for it truly to function the way it is intended.

Last week, the InterAcademy Council (“IAC”), a multinational organization of scientific academies, issued its Review of the IPCC. While it noted an “essential” need for “some fundamental changes to the process and the management structure,” its tenor was generally positive about the contributions the IPCC has made: “[T]he IPCC assessment process has been successful overall and has served society well. The commitment of many thousands of the world’s leading scientists and other experts to the assessment process and to the communication of the nature of our understanding of the changing climate, its impacts, and possible adaptation and mitigation strategies is a considerable achievement in its own right.” The full report can be read here (a discussion of the Himalayan glaciers statement begins on page 23).

Coincidentally, the U.S. Geological Survey released its image atlas on “The Glaciers of Asia” only about a week before the IAC’s report, providing evidence that the Himalayan glaciers are, in fact, receding, although there is still conflicting data about what is actually going on there. That atlas can be seen here.

There is no question that the credibility of the IPCC has been damaged and deservedly so. Himalayan glaciers are vital. Even Al Gore noted in his movie that the Himalayan ice sheet feeds seven of the world’s major river systems, providing water to some 40% of the world’s population. Statements about its demise should not be made lightly.

But at the same time, it is important not to lose an appropriate sense of context. Global climate change is incredibly complex to understand and the volume of information considered by the IPCC in issuing its assessments is large. Nations very much need a body to aid in the digestion of the scientific information and to provide carefully considered evaluations of the implications of that scientific information.

Mistakes can and do occur during peer-review processes, and it is very much my hope that those who see something more sinister than a simple error are mistaken. Long-time editor of the Applied Journal of Physics Steven J. Rothman, a man I knew and deeply respected, once provided a highly apt assessment of the system of peer review by paraphrasing Winston Churchill’s quip about democracy as a form of government: “It is the worst … except for all the others that have been tried.”